Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 06/47] firmware: improve LSM/IMA security behaviour | Date | Thu, 18 Jul 2019 12:01:20 +0900 |
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From: Sven Van Asbroeck <thesven73@gmail.com>
commit 2472d64af2d3561954e2f05365a67692bb852f2a upstream.
The firmware loader queries if LSM/IMA permits it to load firmware via the sysfs fallback. Unfortunately, the code does the opposite: it expressly permits sysfs fw loading if security_kernel_load_data( LOADING_FIRMWARE) returns -EACCES. This happens because a zero-on-success return value is cast to a bool that's true on success.
Fix the return value handling so we get the correct behaviour.
Fixes: 6e852651f28e ("firmware: add call to LSM hook before firmware sysfs fallback") Cc: Stable <stable@vger.kernel.org> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Kees Cook <keescook@chromium.org> To: Luis Chamberlain <mcgrof@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/base/firmware_loader/fallback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/base/firmware_loader/fallback.c +++ b/drivers/base/firmware_loader/fallback.c @@ -659,7 +659,7 @@ static bool fw_run_sysfs_fallback(enum f /* Also permit LSMs and IMA to fail firmware sysfs fallback */ ret = security_kernel_load_data(LOADING_FIRMWARE); if (ret < 0) - return ret; + return false; return fw_force_sysfs_fallback(opt_flags); }
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